The purpose is to create a set of images taken at different zoom positions.

The script takes a number of images starting from the current zoom position.
So if you take 3 pictures, with Zoom Step Size 1, the script will take the first picture at the current zoom position, the second at zoom position +1, and the third at zoom position +3 relative to the start zoom position. A positive Zoom Step Size will zoom in, a negative Zoom Step Size will zoom out. Afterwards the initial zoom position will be restored.

Documentation/Help (save as a small ZoomBracket.txt" file to your /CHDK/SCRIPTS/ folder)